package com.lagou.server;

import com.lagou.server.config.ContextInfo;
import com.lagou.server.config.HostInfo;
import com.lagou.server.config.ServerConfig;
import com.lagou.server.core.MyWebAppClassLoader;
import com.lagou.server.mapper.MappedContext;
import com.lagou.server.mapper.MappedHost;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.Node;
import org.dom4j.io.SAXReader;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;

/**
 * Minicat的主类
 */
public class Bootstrap {

    /**定义socket监听的端口号*/
    private int port = 8090;

    private ServerConfig cfg = new ServerConfig();

    public int getPort() {
        return port;
    }

    public void setPort(int port) {
        this.port = port;
    }


    /**
     * Minicat启动需要初始化展开的一些操作
     */
    public void start() throws Exception {

        loadServconfig(); //内部初始化 loadServlet();
        // 加载解析相关的配置，web.xml


        // 定义一个线程池
        int corePoolSize = 10;
        int maximumPoolSize =50;
        long keepAliveTime = 100L;
        TimeUnit unit = TimeUnit.SECONDS;
        BlockingQueue<Runnable> workQueue = new ArrayBlockingQueue<>(50);
        ThreadFactory threadFactory = Executors.defaultThreadFactory();
        RejectedExecutionHandler handler = new ThreadPoolExecutor.AbortPolicy();


        ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(
                corePoolSize,
                maximumPoolSize,
                keepAliveTime,
                unit,
                workQueue,
                threadFactory,
                handler
        );





        /*
            完成Minicat 1.0版本
            需求：浏览器请求http://localhost:8080,返回一个固定的字符串到页面"Hello Minicat!"
         */
        ServerSocket serverSocket = new ServerSocket(cfg.getPort());
        System.out.println("=====>>>Minicat start on port：" + port);

        /*while(true) {
            Socket socket = serverSocket.accept();
            // 有了socket，接收到请求，获取输出流
            OutputStream outputStream = socket.getOutputStream();
            String data = "Hello Minicat!";
            String responseText = HttpProtocolUtil.getHttpHeader200(data.getBytes().length) + data;
            outputStream.write(responseText.getBytes());
            socket.close();
        }*/


        /**
         * 完成Minicat 2.0版本
         * 需求：封装Request和Response对象，返回html静态资源文件
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();

            // 封装Request对象和Response对象
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());

            response.outputHtml(request.getUrl());
            socket.close();

        }*/


        /**
         * 完成Minicat 3.0版本
         * 需求：可以请求动态资源（Servlet）
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();

            // 封装Request对象和Response对象
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());

            // 静态资源处理
            if(servletMap.get(request.getUrl()) == null) {
                response.outputHtml(request.getUrl());
            }else{
                // 动态资源servlet请求
                HttpServlet httpServlet = servletMap.get(request.getUrl());
                httpServlet.service(request,response);
            }

            socket.close();

        }
*/

        /*
            多线程改造（不使用线程池）
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            RequestProcessor requestProcessor = new RequestProcessor(socket,servletMap);
            requestProcessor.start();
        }*/



        System.out.println("=========>>>>>>使用线程池进行多线程改造");
        /*
            多线程改造（使用线程池）
         */
//        while(true) {
//
//            Socket socket = serverSocket.accept();
//            RequestProcessor requestProcessor = new RequestProcessor(socket,servletMap);
//            //requestProcessor.start();
//            threadPoolExecutor.execute(requestProcessor);
//        }

        System.out.println("=========>>>>>>使用线程池进行多线程改造");
        /*
            V 4.0 版本改造
         */
        while(true) {

            Socket socket = serverSocket.accept();
            RequestProcessor requestProcessor = new RequestProcessor(socket, servletMap, hostMap);
            threadPoolExecutor.execute(requestProcessor);
        }



    }


    private Map<String,HttpServlet> servletMap = new HashMap<String,HttpServlet>();
    private Map<String,MappedHost> hostMap = new HashMap<String,MappedHost>();
    private Map<String,MappedContext> contextMap = new HashMap<String,MappedContext>();

    /**
     * 加载解析web.xml，初始化Servlet
     */
    private void loadServlet(ContextInfo contextInfo) {
        String contextName = contextInfo.getContextName();
        InputStream resourceAsStream = this.getClass().getClassLoader().getResourceAsStream("web.xml");
        SAXReader saxReader = new SAXReader();

        try {
            Document document = saxReader.read(resourceAsStream);
            Element rootElement = document.getRootElement();

            List<Element> selectNodes = rootElement.selectNodes("//servlet");
            for (int i = 0; i < selectNodes.size(); i++) {
                Element element =  selectNodes.get(i);
                // <servlet-name>lagou</servlet-name>
                Element servletnameElement = (Element) element.selectSingleNode("servlet-name");
                String servletName = servletnameElement.getStringValue();
                // <servlet-class>server.LagouServlet</servlet-class>
                Element servletclassElement = (Element) element.selectSingleNode("servlet-class");
                String servletClass = servletclassElement.getStringValue();


                // 根据servlet-name的值找到url-pattern
                Element servletMapping = (Element) rootElement.selectSingleNode("/web-app/servlet-mapping[servlet-name='" + servletName + "']");
                // /lagou
                String urlPattern = servletMapping.selectSingleNode("url-pattern").getStringValue();
//                servletMap.put(urlPattern, (HttpServlet) Class.forName(servletClass).newInstance());
                MappedHost mappedHost = new MappedHost();
                MappedContext context = new MappedContext();
                context.setContextPath(contextName);
                mappedHost.getContextMap().put(contextName, context);
                String classPath = contextInfo.getApppath() + "/" + contextInfo.getContextName(); // /Users/ceven/webapps/demo1/
                System.out.println("aaa.contextPath: " + classPath);
                MyWebAppClassLoader classLoader = new MyWebAppClassLoader(classPath);
                context.setClassLoader(classLoader);
                HttpServlet httpServlet = (HttpServlet) classLoader.loadClass(servletClass).newInstance();
                System.out.println("instance: " + httpServlet);
                context.getServletMap().put(urlPattern, httpServlet);
                hostMap.put("localhost", mappedHost);
            }



        } catch (DocumentException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }

    }

    /**
     * 加载解析web.xml，初始化Servlet
     */
    private void loadServconfig() {
        InputStream resourceAsStream = this.getClass().getClassLoader().getResourceAsStream("server.xml");
        SAXReader saxReader = new SAXReader();

        try {
            Document document = saxReader.read(resourceAsStream);
            Element rootElement = document.getRootElement();

            List<Element> selectNodes = rootElement.selectNodes("//Server//Service//Connector");
            for (int i = 0; i < selectNodes.size(); i++) {
                Element element =  selectNodes.get(i);
                String portstr = element.attributeValue("port");
                cfg.setPort(Integer.parseInt(portstr));
                // <servlet-name>lagou</servlet-name>
                Element hostElement = (Element) element.selectSingleNode("//Engine//Host");
                String hostName = hostElement.attributeValue("name");
                String appBase = hostElement.attributeValue("appBase");

                HostInfo hostInfo = new HostInfo();
                hostInfo.setName(hostName);
                hostInfo.setApppath(appBase);

                // 扫描指定目录的 项目文件
                File dir = new File(appBase);
                File[] apps = dir.listFiles();
                for (File file : apps) {
                    if(file.isDirectory()) {
                        ContextInfo context = new ContextInfo();
                        context.setApppath(appBase);
                        context.setContextName(file.getName());
                        context.setName(hostName);
                        loadServlet(context);
                    }
                }
            }
            System.out.println("监听端口号：" + cfg.getPort());


        } catch (DocumentException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }

    }


    /**
     * Minicat 的程序启动入口
     * @param args
     */
    public static void main(String[] args) {
        Bootstrap bootstrap = new Bootstrap();
        try {
            // 启动Minicat
            bootstrap.start();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
